ObjectiveTo investigate mothers’ knowledge of reducing the risks for sudden infant death syndrome (SIDS) and attitudes towards safer sleep practices.Design and settingA cross-sectional survey was carried out in deprived areas of Bristol, UK. Recruitment took place in 2014 at local health visitor-led baby clinics.ParticipantsOf 432 mothers approached, 400 (93%) completed the face-to-face survey. Participants with infants at ‘higher’ risk of SIDS (using an algorithm based on a previous observational study) were compared with those at ‘lower’ risk.Main outcome measuresThe survey asked participants to recall three SIDS risk reduction strategies (unprompted), and scored responses to 14 SIDS risk-related infant sleep scenarios (prompted).ResultsOverall, 48/400 (12%) mothers were classified as higher risk. Mothers in the higher risk group were less likely to breast feed (multivariate OR=3.59(95% CI 1.46 to 8.86)), less likely to be able to cite two or more unprompted correct SIDS risk reduction strategies (multivariate OR=2.05(95% CI 1.02 to 4.13)) and scored lower on prompted safer sleep scenarios overall.Notably, only 206/400 (52%) of all mothers surveyed (33% in the higher risk group) from these deprived areas in Bristol identified infant sleep position as a risk reduction strategy for SIDS, despite 25 years of campaigns.ConclusionsMothers in the higher risk group were disadvantaged when it came to some aspects of knowledge of SIDS risk reduction and attitudes to safer sleep. The initial ‘Back-to Sleep’ message that dramatically reduced these deaths a generation ago needs more effective promotion for today’s generation of mothers.